fuel guage stuck beyond full - Second Generation Pontiac Firebird (1970 - 1981) - Firebird Nation

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fuel guage stuck beyond full


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4 replies to this topic

#1 msammy93

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Posted A week ago

So had to remove my gas tank in order to replace my leaf springs. Now the fuel gauge is stuck beyond full even though their is only 1.5 to 2 gallons of gas in the tank. I am sure I put the plug on the sending unit back and I even repaired a part of the wire that was damaged. The ground is also screwed into a cleaned out area.

 

Could a bad gauge cause it to stick beyond full? Kind of strange considering it was working fine before I removed it.



#2 Aus78Formula

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Posted A week ago

Beyond full means the ground wire is likely damaged or not connected. Check it first before going further.

#3 ZumpTA

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Posted A week ago

Beyond full means the ground wire is likely damaged or not connected. Check it first before going further.

 

^^^^^ THIS!

 

Add corroded to the list as well.  If you had to repair a wires insulator, there could be corrosion in the harness.  Any green or black copper anywhere is bad.  Unfortunately, a nearly 40 year old wire can look brand new on the outside, but could also be the farthest thing from it on the inside. Copper might be shiny on one end and black on the other.  Corrosion can increase resistance in the wire to the point the circuits voltage is imbalanced causing "gremlins", or increase the resistance of the wire so high, it's like trying to use air to conduct the electricity.   As it was fine before, it's something very simple, and least likely the gauge.


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#4 msammy93

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Posted A week ago

so dropped the tank and the sender and ground wire is perfectly fine. I cleaned up the ground and put the tank back in. Gauge was still pegged out. I then took the gauge out and tested the wires. The sending wire was reading 40 omhs. The voltage when ignition was on was 11.2v and the ground was working. it seems that the gauge got pegged out and stuck so I ordered a new gauge. Will update if the new gauge doesn't work.



#5 fireforeffect

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Posted 3 days ago

Sorry, responded to your other post... it's your sending unit. Went thru this several weeks ago and narrowed it down to the sender. The resistor was bad. Replaced w/ a good quality part, ran the ground up into the trunk w/ a positive connection, and all works fine. 






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